使用一维指针创建对象数组：
//============================================================================
// Name : main.cpp
// Author : ShiGuang
// Version :
// Copyright : sg131971@qq.com
// Description : Hello World in C++, Ansi-style
//============================================================================
#include <iostream>
#include <string>
using namespace std;
int nextStudentID = 1;
class StudentID
{
public:
StudentID()
{
cout << "StudentID()" << endl;
value = nextStudentID++;
cout << "value:" << value << endl;
}
~StudentID()
{
--nextStudentID;
cout << "~StudentID()" << endl;
}
protected:
int value;
};
class Student
{
public:
Student(string pName = "noName")
{
cout << "Student()" << endl;
name = pName;
cout << "name:" << name << endl;
}
~Student()
{
cout << "~Student()" << endl;
}
protected:
string name;
StudentID id;
};
int main(int argc, char **argv)
{
int i;
cin >> i;
Student *p = new Student [i];
delete[] p;
cout << "nextStudentID:" << nextStudentID << endl;
return 0;
}
结果：
>>3 StudentID() value:1 Student() name:noName StudentID() value:2 Student() name:noName StudentID() value:3 Student() name:noName ~Student() ~StudentID() ~Student() ~StudentID() ~Student() ~StudentID() nextStudentID:1
使用二维指针创建动态数组：
//============================================================================
// Name : main.cpp
// Author : ShiGuang
// Version :
// Copyright : sg131971@qq.com
// Description : Hello World in C++, Ansi-style
//============================================================================
#include <iostream>
#include <string>
using namespace std;
int nextStudentID = 1;
class StudentID
{
public:
StudentID()
{
cout << "StudentID()" << endl;
value = nextStudentID++;
cout << "value:" << value << endl;
}
~StudentID()
{
--nextStudentID;
cout << "~StudentID()" << endl;
}
protected:
int value;
};
class Student
{
public:
Student(string pName = "noName")
{
cout << "Student()" << endl;
name = pName;
cout << "name:" << name << endl;
}
~Student()
{
cout << "~Student()" << endl;
}
protected:
string name;
StudentID id;
};
int main(int argc, char **argv)
{
int i, j;
string temp;
cin >> i;
Student **p = new Student *[i];
for (j = 0; j < i; j++)
{
cout << "j:" << j << endl;
cin >> temp;
p[j] = new Student(temp);
cout << "nextStudentID:" << nextStudentID << endl;
}
for (j = i - 1; j >= 0; j--)
delete p[j];
// delete[] p; // 这句话好像没作用
cout << "nextStudentID:" << nextStudentID << endl;
return 0;
}
结果：
>>3 j:0 >>shiguang1 StudentID() value:1 Student() name:shiguang1 nextStudentID:2 j:1 >>shiguang2 StudentID() value:2 Student() name:shiguang2 nextStudentID:3 j:2 >>shiguang3 StudentID() value:3 Student() name:shiguang3 nextStudentID:4 ~Student() ~StudentID() ~Student() ~StudentID() ~Student() ~StudentID() nextStudentID:1
两者的区别：
一维指针在建立指针的时候，申请并创建了三个对象。
二维指针在建立指针的时候，只创建了一个指针数组（即3*4Byte），数组里面的元素用来存放三个对象的地址，各个对象地址在后面由new创建获得。所以对应的delete函数应该是delete p[j]；而不是delete[] p。